Duplicating



June 15, 1926.

D. GESTETNER DUBLI CATING M M m/ w L f, v wf 7. .w www a e MOM ad vm ,MMM 1 CZ i 34 2 o Y 40.

a im W mlm. www? Zay @www Qu Yflnzb MH. w d@ vm mz @70 mn wd d Zw m m a S a Patented J une 15,1926.

4UNITED STATES .PATENT OFFICE.

DAVID GESTETNER, l' LODON, ENGLAND, ASSIGNOB TOA'D. GESTETNER, LIIITED,

0l' LONDQN, ENGELA'I'D'. p v

nurmcarme.

Application med December 9, 1991, Serial' No. 521,240, and in Great Britain December 15, 1920.

"This invention relates to the method of v duplicating involvin 'the use of stencils, comprisin a stenci layer produced by photograp lc means on a porous support as',

5 for instance, Yoshino aper. 4

Such stencils are ordinarily produced by exposing to the action of light, a sheet of sensitizedA gelatine on a suitable support b'ehind the matter to be reproduced or a negative'or diapositive produced therefrom and then after development transferring the image to asheet of Yoshino paper.

The object'of the p resent invention is to provide improvements in the production of 16 such stencils.

v According to the invention theA stencil layer is roduced by causin a silver ima e e formed y the action of ligt upon a .lig t sensitive silver salt to yinteract chemically for instance, b1-v 20 with a composition, as

chromated elatine, in order to change the solubility o thecomposition in a medium used as a developer. v l 1 The invention in one phase' comprises producing a print' by the action of light upon a silver compound such, forv instance, as is employed'in `coating bromidef paper, and bringing together the print and a pellicle of a composition adapted by the chemical action of the silver ima e on the colloid to change in ect of 1ts solubility in a developing me um, under conditions to eff fect such change, and developing the pellicle of' composition.

The silver'image may be treated, if necessary, inv order to cause 1t to effect thedesired changes in the composition, or the composition ma container be treated with an agent adaptedy to be acted upon b the silver image, in order that the solu ility of the composition may be affected in the desired manner. f f

The pellicle of composition may be coated on .atemporary support from which yit will be transferred-to ana'l support of a porous character, as for instance Yoshino aper, or

it may in the rst instancebe coate final supportin which case it may be desirable to bring-the back of the coated support into contact with the silver print composition, in order to b the image, with a medium of known characon such Alternatively, the material ada ted to act as the final support may be coate or treated with a composition containing a suitable light sensitive silver compound and after producing thereon a silver print, a pellicle of a suitable composition, as -for instance, bichromated gelatine, may be applied thereto, in conditions adapted to eii'ect the desired change in thexsolubility of the composition. The silver print in either case may be treated, if the pellicle or la er is a gelatine each or reverse ter such as a solution of potassium bich'romate, potassium ferricyanide, and potassium bromide. Another phase of the inventioncomprises' producing y photographic means a silver image in a layer of an. emulsion of a light sensltive silver salt lin unhardened elatine or a like material the solubility o which in a medium used subsequently as a developer (hot water in the case of gelatine) is adapted to be chan ed in accordance with the intensity of ight action on the said la er, treating the said layer to effect the deslred change in solubility and developing the treated layer, in order to dissolve or wash out the portions of the gelatine or the like which have not been .insolubilized.

' The layer of emulsion may be constituted by a gelatine `emulsion resembling the emulsion used in making bromide paper, but which however, is not hardened, and the support coated with this emulsion may be exposed, treated inthe usual'wa to produce a silver print, after which 1t is treated if necessary with an .agent ada ted, with or without further exposure to light, to. chan'ge the solubility ofthe gelatine in the medium subsequentl used as a developer at the 1i ht aiected'or ight unaffected portions an finally developed.

Alternatively, a supportl similarly coated, after exposure and development of the silver image may be sensitized'by meansof a suitable a ent as, for instance, a bichromate exposedg to the action of light, if necessary 0r desirable,

and redeveloped to remove accompanying drawings,

those ortions' of the i elatine layer which have en less affecte by the action of light as the result of the silver image preventing or reducing the action of light upon lthe sensitizing agent.

e The gelatine emulsioni'in this phase of the invention may be supported o n a porous material, as for instance, Yoshmo paper,

comprises exposing e reproduced and using the image thus roduced in one or other of the manners indicated above in producing a stencll and thereby avoiding the necessity of producing first a negative and then a diaposltive from the negative and inally a print from the diapositive adapted for use as a stencil.

In order that the invention may be better understood, reference may be 'had to the in which:

Figures land 2 are respectively a section and elevation of aprint produced by the action of lighten a silver compound;

Figure llshows in section a rint as shown in Figures `1 and 2 in contact with a sheet of paper coated with bichromated gelatine; Figure`4 is a view showing the sheet of aper coated with gelatine after it hasbeen developed while Figure 5 is a section of a sheet as shown in Figure 4 with developed gelatine layer 1n contact with a sheet of Yoshino paper.

Figure 6 is a view in section of the stencil;

Figure 7 is a view in section of a sheet of Yoshino paper coated with bichromated gellatine and in contact with a silver negative print of the matter to be reproduced;

Figures 8 and 9 are views in section of a -sheet of Yoshino paper treated with a light sensitive silver counpoundv respectively before and after exposure to the action of light;

Figure 10 shows arp'rint asin Figure 7 in contact with a sheet of paper coated with bicromated gelatine in order that the reduced silver may nsolubilize portions of the bichromated gelatine; v y

Figure 11 is a plan view showing the comy pleted stencil;

Figure 12 1s a'l view in section'of a sheet of papencoated with-a bichromated gelatine emulsion, contaming a light sensitivesilver sa'l-twlth a layerk of wax between the emulsion 4and the paper, support;

' Figure 13-is a view in section of thesame ,afterl exposure l to the action of lightand development of4 the silver imageuin lcntact witttlie shet'of Yoshino paper, the paper bichromated gelatine Vfor use as' astencil. i

backing forming the ori inal su port for theA eing s own in the process of removal,

Figure 14 being a similar view of the sheet of Yoshino paper after it has been treated in order to remove the portions of the coating transferred to it which have been rendered insoluble' in the developer; y

Figure 15 illustrates a sheet of Yoshino paper coated with a bichromated gelatine emulsion containing salt, while l Figure 16 is a view in section of the same after it has 'been exposed to the action of light, developed'in order to reduce the light a light sensitive silverv adected silver salt and treated with: hot l water in order to remove the still soluble gelatine, and' Figure 17 is a view in elevation of the same. y e Referring to Figures 1 to 5, 1- indicates a paper support, 2 portions of the light sensitive coating thereon which have been affected by light, 3 the ortions which have been unaffected by lig t. 4, in Figure 3, illustrates a sheet of paper provided with a coating of bichromated gelatine, the portions 5 of which have been rendered insoluble, whereas the portions 6 have remained soluble in consequence of their beingunaeted upon by the reducedl silver, the said sheet having its gelatine coating in contact with a silver print, as shown in Figures 1 and 2. v

Figure 4 illustrates in yelevation the sheet -of paper 7 coated with bichromated gelatine after ithas been stripped from the silver,

print and developed with hot water, the reference v8 indicating .the portion from which the gelatine which has not been rendered insoluble has been removed.

In Figure, 9 indicatesa sheet of Yoshino vpaper and 10 a coating of gelatine thereon, the sheet of paper 7 acting as a support for the same during development, being also in contact with the gelatine.

Figure-6 isa section of the finished stencil, in which like partsl are indicated by like references, after lthe sheet of paper acting as temporary support for the gelatine has been stripped olf.

Referring to Figure 7, 11J is a sheet of Yoshmo paper, 12 a coating obichromated gela-tine thereon, 13 the light affected` portions of a light sensitive positive, 14 the portions thereof Which have not beenzaffected by l1gh t, and 15 the support for the said composition.

.In Figure 8, lindicates a sheetof Yoshmo paper, 17 a coating of a light sensitive silver compound thereon, while in Figure 9, 18 indicates the portionsof the silver compound which have been aiectedby'light and 19 the portions .which have not been so afpaper or the like. from the bichromated gelatine after treat- Similar references are used in Figurel() to denote like parts,'the print as shown in section in Figure 9 being in thisiigure illus. trated in contact. with a coating of bichromated gelatine 20 on a support 21 formed of This support is stripped ment to cause the silver image .tointeract with'the'bichromated elatine whereby portions of the same wi have been rendered insoluble. After stripping the support from the bichromated gelatine and treating 'the latter 'in order to remove'the'still-soluble portions a stencil, as shown in Fi 11, is obtained, the reference 22 in this gure indicating the Yoshino paper while 23 represents the'insolubilized bichromated gelatine In Figure 12, 24 indicates a temporary support of sheetmaterial, 25 a coating of Wax or the like thereon and 26 a coating of bichromated gelatine emulsion containing a light sensitive silver lsalt. By exposure of the coated support certain areas of the light sensitive coating will be ai'ected by light and will be reduced on development, the reduced silver reacting with the bichromate present in the gelatine emulsion, converting the same into chromium salts which render the portions of the gelatine, where such action has takenplace, insoluble.l

In VFigure 13, 27 indicates a -slieet of Yoshino paper which Ahas been broughtinto contact andcaused to adhere to the bichromated gelatine.

tine in process 4of removal.

In Figure 14, 28 indicates the Yoshino l salt supported thereon, while in Figure 16,

33 indicates a sheet of Yoshino paper, 34 the portions of the bichromated gelatine emulsion which have been 1 endeedl insoluble by exposure to light and .35 the a rtures or 'openings therein through which t e ink will be caused to passim the operation of duplieating. v

Figu stencil, v like references.

re'17 is a view in elevation of the parts being indicated by like Having now described my invention what I 'I claim as new and desire to secure by Let- Yoshino paper base, which comprises pro-l ducing av print bythe action of light upon ters Patentis V 1. The process of producing stencils on a a silver bromide emulsion coated on'a support, bringingl together .the rint on said support and a pellicle o composition This 'figure' shows the o riginal support for the bichromated gelaadaptedby the chemical action of the silver image on the composition of which the pellicle is formed to change the same in retine under conditions adapted to cause the` silver image to form salts-of chronium as a' base in the bichromated gelatine, whereby portions of the gelatine will be rendered insoluble, developing the pellicle thus treated with hot water and transferring the developed pellicle to a sheet of Yoshi-no paper.

3. The process of producing stencils on a Yoshino paper base, which comprises caus' ing an image formed by thev action of light on a light sensitive silver salt to effect -a chemical change -in bicliromated gelatine, whereby areas of the bichromated gelatine will be rendered insoluble in hot water and `subjecting the bichromated gelatine after such treatment to the action of hot water to vremove the still soluble portions, therebyy obtaining' aninsoluble gelatine image adapted for use asp-a stencil.

4. The process of producing stencils on a Yoshino paper base,.,which comprises causing an image formed by the action of light on a light sensitivesilver salt to eect a chemical change in bichromated gelatine," whereby areas of the bichromated gelatine will lbe rendered insoluble in hot water and subjecting the Ibichromated gelatine after such treatment tothe action of hot water to remove the still soluble portions, and transferring the insoluble gela-tine image thus obtained to a sheet of Yoshino paper.

5. The process of producing stencils on a Yoshino paper base, which comprises exincluding a light-sensitive silver lcompound r10ol to projected light in order to produce therein a latent image'of the `matt/er to be repro duced, developing said image, bringing together said. developed image and a pellicle of a lcomposition adapted by the chemical action of 'the silver image von the composition of which the pellicleA is formed `to change the samein respect "to its solubility in a developing medium, under conditions to eiect such change, developing the pcllicle ofr composition and transferring thef developed' pellicle to a sheet of Yoshino paper.

6. The process of producing stencils on a Yoshino paperbase, which comprises ex posing a support providedv with a'coating including a light sensitive silver compoun to projected light in order to produce therein `a latent image of the matter to be .re-

produced, developing said image, bringing together said developed image and a pellic-le of bichromated gelatine under conditions adapted to cause the silver image to form salts of chromium as a base in the bichromated gelatine,- wherebyA portions of 10 d the ygelatine will be rendered insoluble, de

thus treated with hot velop-ing thel pelliele water and transferringy the developed `pellicle to a sheet of Yoshino paper.

In testimony whereof I have-signed my 15 name to this speeiication.

DAVID GESTEjrNER. 

